Fertility control process employing ethanolamines

ABSTRACT

1. THE PROCESS FOR REDUCING MAMMALIAN FECUNDITY WHICH COMPRISES ADMINISTERING TO FERTILIZED FEMALE MAMMAL BY THE ORAL OR PARENTERAL ROUTED DURING THE PERIOD FOLLOWING OVULATION AND PRIOR TO THE TIME WHEN IMPLANTATION OCCURS AN EFFECTIVE IMPLANTATION PREVENTING DOSE OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF A COMPOUND HAVING THE FORMULA   R1-NHCH2CH2-O-R2   WHEREIN R1 IS SELECTED FROM THE GROUP CONSISTING OF LOWER ALKYL HAVING 2 TO 5 CARBON ATOMS INCLUSIVE, LOWER ALKENYL HAVING 3 TO 5 CARBON ATOMS INCLUSIVE, CYCLOALKENYL HAVING 4 TO 5 CARBON ATOMS, CYCLOALKYL HAVING 3 TO 5 CARBON ATOMS INCLUSIVE, DIMETHYLAMINO, PYRROLIDINYL, AND AN ALKYL SUBSTITUTED CYCLOALKYL WHEREIN SAID ALKYL SUBSTITUENT HAS FROM 1 TO 3 CARBON ATOMS INCLUSIVE; AND SAID CYCLOALKYL HAS 3 TO 5 CARBON ATOMS INCLUSIVE; R2 IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN BENZOYL AND AN ALKANOYL FROM 2 TO 24 CARBON ATOMS INCLUSIVE; OR R1-NH IS PYRROLDDINYL AND A PHARMACEUTICALLY ACCEPTABLE ACID ADDITION SALT OF SAID COMPOUND

United States Patent O Int. 01. A0111 9/22 US. Cl. 424274 21 ClaimsABSTRACT OF THE DISCLOSURE A pharmaceutical process for preventingpregnancy or reducing litter size which comprises post-coitaladministration of compounds having the formula to a female mammal isdisclosed. The substances useful in this invention are 2-(alkyl-,alkenyl, cycloalkyl-, cycloalkenyl-amino)ethano1s, esters and acidaddition salts thereof. Estrogenic effects are absent.

CROSS REFERENCE TO RELATED APPLICATIONS This patent application is acontinuation-in-part of pendpending US. patent application Ser. No.73,192 filed Sept. 17, 1970, and now abandoned which is acontinuation-inpart of US. patent application Ser. No. 11,873 filed Feb.16, 1970, now abandoned.

FIELD OF THE INVENTION This invention is in the field of drugbio-affecting, and body treatment and involves administration of2-(alkyl-, alkenyl-, cycloalkenyl-, cycloalkyl-amino)-ethanols and theircarboxylic ester derivatives or an acid addition salt thereof formammalian fertility control.

DESCRIPTION OF THE PRIOR ART Oral contraceptive products have now beenin widespread use for 10 to 12 years. Products currently in use areeffective by creation of a state of pseudopregnancy with concomitantprevention of ovulation. These prod ucts involve combinations ofestrogenic and progestogenic synthetic steroid hormones which areadministered either in combination or sequence. Refer to, for example,New Drugs Evaluated by AMA Council on Drugs 1967 Edition, pp. 381399,American Medical Association, Chicago, Illinois.

During this period, research for non-hormonal substances affectingfemale mammalian fertility has gone forward and some progress in thisarea has been made. Compounds having a structural relationship todiethylstilbestrol and hexestrol have been one of the most intensiveareas of study in this regard. Refer to Cornelius K. Cain Annual Reportsin Medicinal Chemistry, 1968 pp. 191-196, Academic Press, New York 1969.These substances are diphenyl or triphenyl ethylenes and ethanes. Nosubstance from this area of chemical investigation has come into use asan oral contraceptive agent, however. The Cain reference cited alsodiscussed findings with respect to lowering of fertility in male rats byu-glycerol monochlorohydrin, the only simple compound heretofore ofinterest in the field.

A number of 2-(-alkyl-, alkenyl, cycloalkyl-,cycloalkenyl-amino)ethanols such as 2 (ethylamino)ethanol,2-(tert.-butylamino)ethanol and 2 (cyclopentylamino) ethanol have beendescribed in the literature. For instance, 2 (isopropylamino)ethanol isa simple amino 3,845,214 Patented Oct. 29, 1974 ICC alcohol which hasbeen known for many years. While a variety of complex esters of it havebeen the subject of medical and pharmacological investigations asanalgesics and antispasmodics, nothing has been reported about thepharmacological, toxicological, or medical use of the amino alcoholitself.

Screening data with respect to the anti-cancer action of2-(isopropylamino)ethanol has been reported by Leiter and Schneidermanin Cancer Research Vol. 19, p. 116 (1959). The substance was inactiveagainst several mouse tumors.

US. Pat. No. 3,167,475 dated Jan. 26, 1965, of S. Gottfried et al.,deals with anti-anaphylactic compositions containing amino ethanolderivatives such as 2-(methylamino)ethanol, 2 (ethylamino)ethanol, 2(dimethylamino)ethanol, 2-(diethylamino)ethanol, and various saltsthereof. The Gottfried et al., compositions are of particular interestas antihistaminic compositions in which the amino ethanol is combinedwith an antihistamine drug for the treatment of allergic conditions, ause quite unrelated to the present invention. More recently 2(ethylamino) ethanol, 2-(isopropylamino)ethanol and 2(tern-butylamino)ethanol have been disclosed in Belgium Patent 741,35 3as having coccidiostatic properties.

SUMMARY OF THE INVENTION This invention relates to a process forreducing mammalian fecundity by oral or parenteral administration ofsubstances characterized by Formula I and non-toxic pharmaceuticallyacceptable acid addition salts thereof.

The substances of Formula I are either ethanolamines or carboxylic acidester derivatives thereof. In Formula I, R is lower alkyl, loweralkenyl, cycloalkenyl, cycloalkyl, alkyl substituted cycloalkyl,dimethylamino, and pyrrolidinyl; R --NH can also be incorporated in anitrogen heterocycle such as pyrrolidine to provide a pyrrolidinylradical; R is hydrogen, an alkanoyl radical or a benzoyl radical.

It is to be understood that the term lower alky as employed hereinincludes both straight and branched chain hydrocarbon radicals havingfrom 2 to 5 carbon atoms inclusive. Illustrative of lower alkyl radicalsare ethyl, propyl, isopropyl, l-butyl, l-methylpropyl (sec.- butyl),2methylpropyl, tart-butyl, n-pentyl, l-methylbutyl, 2-methylbutyl, andthe like.

The term lower alkenyl as used herein for the meaning of R includes bothstraight and branched chain alkenyl radicals having from 3 to 5 carbonatoms inclusive and is illustrated by the radicals 2-propenyl (allyl),2- methyl-2-propenyl, 3-methyl-2-butenyl, 3-butenyl, and the like.

The term cycloalkenyl as used herein for one of the meanings of R inFormula I, stands for a radical having 3 to 5 carbon atoms inclusive andis illustrated by 2- cyclobutenyl, 2-cyclopentenyl, 3-cyclopentenyl, andthe like.

The term cycloalkyl as used herein for one of the meanings of R includessuch radicals as cyclopropyl, cyclobutyl, and cyclopentyl.

The term alkyl substituted cycloalkyl as used herein for one of themeanings of R means a cycloalkyl radical having 3 to 5 carbon atomsinclusive which has an alkyl substituent selected from the groupconsisting of methyl, ethyl, n-propyl, and isopropyl.

The term alkanoyl as used herein for one of the meanings of 'R is analkanoyl radical having from 2 to 24 carbon atoms. Exemplary ofcarboxylic acids corresponding to the alkanoyl radicals are: acetic,butanoic, hexanoic, octanoic, decanoic, dodecanoic, tetradecanoic,

hexadecanoic (palmitic), octadecanoic (stearic), eicosanoic, docosanoic,tetracosanoic, Z-methylpropionic, 2-dimethylbutanoic, 3-methylbutanoic,3-ethylbutanoic, and 3,3-dimethylbutanoic.

Substances characterized by Formula I which are useful in the fertilitycontrol process of the present invention are readily prepared accordingto methods well-known to those skilled in the art. For example, oneconvenient way of preparing ethanol amines of Formula I, wherein R ishydrogen, is by catalytic (e.g. PtO reductive alkylation of aminoethanolwith an aldehyde or a ketone as described in R. B. Wagner and H. D.Zook, Synthetic Organic Chemistry, Chapter 24. The aldehyde or ketonethen becomes the R substituent in the ethanol amines of Formula I.Reductive alkylation of aminoethanol with cyclopentanone according tothe following equation is representative of this method.

Another Way of preparing the substances of Formula I wherein R ishydrogen is by the alkylation of an amine represented by R NH with2-chloroethanol in the presence of an acid acceptor such as potassiumcarbonate. Alkylation of cyclopropylamine with 2-chloroethanol accordingto the following equation illustrates this method KzCOa NH: CICHzCHzOHAnother convenient method of obtaining ethanol amines of Formula Iwherein R is hydrogen is by the reaction of an R NH amine with ethyloxallyl chloride to provide the ethyl ester of an oxalamide. Thismaterial is reduced with lithium aluminum hydride to proVide the ethanolamine of Formula I wherein R is hydrogen. This method is illustrated inthe following reaction scheme which represents the preparation of 2-(n-propylamino)ethanol.

Esters of Formula I wherein R is an alkanoyl or benzoyl radical areprepared by standard methods such as reaction of an amino alcohol withan alkanoyl or benzoyl chloride in an inert reaction solvent.

It has been discovered that substances of Formula I are effectivefertility control agents in mammals when administered orally orparenterally to the female of the species in doses ranging from about0.015 to 3 millimole of the active ingredient per kilogram of bodyweight. The ethanol amines and esters of Formula I are particularlyeffective in the reduction of pregnancy when administered from the timeof mating (coitus) to prior to the time when implantation of thefertilized ovum is complete and placental development commences.

A preferred group of compounds useful in the present fertility controlprocess are those of Formula I wherein the R radical is isopropyl,cyclopentyl, cyclobutyl, or 2-cyclopentenyl and R is hydrogen or analkanoyl radical having from 2 to 16 carbon atoms. Compounds which areparticularly preferred in practicing the present process are:

2- isopropylamino ethanol, 2-( cyclopentylamino ethanol, 2-(cyclobutylamino ethanol, 2- (2-cyclopentenyl ethanol.

Oral or parenteral administration of the substances of Formula I or anacid addition salt thereof to a mammal during the period betweenfertilization and implantation of the fertilized ovum interferes withthe production of offspring. The dose can be adjusted so as to eitherprevent pregnancy, or to merely reduce litter size. Thus, the substancesof Formula I are effective antifertility agents useful in the process ofthe present invention in control of animal populations for demographic,sociological, medical, or rodent control purposes. For example,2-(cyclopentylamino)ethanol, 2-(2 cyclopentenylamino)ethanol and 2(isopropylamino)ethanol are effective when administered orally orparenterally to the female of the species in doses in the range of 0.1to 1 millimole per kilogram of body weight.

The substances of Formula I and their pharmacologically acceptable saltsare non-toxic and substantially free of other pharmacologic effects uponoral or parenteral administration to a mammal at doses which produce theantifertility effect on the female of the species. The LD values for theacute toxicity in the mouse treated orally withZ-(isopropylamino)ethanol or 2-(cyclopentylamino) ethanol isapproximately 580* and 4000 mg./k'g. body weight, respectively. Oral orintraperitoneal administration of 2-(cyclopentylamino)ethanol as aneutralized aqueous solution to mice at doses up to 250 to 500 mg./ kg.produces no pharmacological effect other than the antifertility actionwhich is the subject of this invention. The intraperitoneal ALD of2-(cyclopentylamino)ethanol hemimucate in mice is 950 mg./kg. bodyweight.

In the practice of the present invention, it is preferred to employ apharmacologically acceptable acid addition salt of the substances ofFormula I since the amino alcohols and esters are relatively strongbases and might therefore be irritating to the gastro-intestinal mucosaor other tissues with which they come in contact on oral or parenteraladministration. The term pharmacologically acceptable acid addition saltis intended to refer to those salts of the substances of Formula I inwhich the anion does not contribute significantly to the toxicity nordetract from antifertility action of the basic compound. Suitable saltsinclude particularly those of the strong inorganic acids includinghydrochloric, hydrobrornic, hydroiodic, sulfuric, nitric, and phosphoricacids. It also includes both the strong organic acids such as the aryland aliphatic sulfonic acids and acid sulfates such as p-toluenesulfonicacid, methanesulfonic acid, lauryl sulfuric acid, etc. and the non-toxiccarboxylates including salts of benzoic,

acetic, propionic, citric, mucic, lactic, tartaric, maleic, and

other acids useful in forming salts for pharmaceutical purposes. Thesalts may be prepared by a simple neutralization process from theethanol amine bases or esters of Formula I as is well-known to thoseskilled in the art.

The dosage figures given herein refer to the dose of active ingredient,a term which comprehends the ethanol amine bases or esters. Whenemploying an acid addition salt of the amino alcohol bases or esters ofFormula I, the size of the dose should be adjusted to take into accountthe percent of active ingredient contained in the salt. For example,amino alcohols such as 2-(isopropylamino)ethanol or2-(cyclopentylamino)ethanol are relatively low molecular weightsubstances; thus, when administered in the form of a salt of an acidwith a relatively heavy molecular weight such as mucic acid, asubstantial proportion of the salt is inert material on a weight basis.

Substances characterized by Formula I can be employed in admixture withthe usual pharmaceutical carriers in carrying out the fertility controlprocess of the present invention. Consideration should be given to thoseorganic and inorganic carrier substances which are suitable for oral andparenteral application and which do not enter into reaction with theethanol amines and esters of Formula I. Suitable carriers by way ofexample are water, vegetable oils, polyethylene glycol, gelatin,lactose, starch, magnesium stearate, talc, and so on. For

oral application, tablets, capsules, powders, granules, syrups, elixirs,liquid suspensions, or solutions are especially preferred. Thesubstances of Formula I are incorporated with a pharmaceutical carrierin unit dosages providing from to 500 mg. of active ingredient andeffective amounts thereof are administered to mammals in practicing thefertility control process of the present invention.

A preferred unit dosage suitable for oral or parenteral administrationto female mammals comprises a pharmaceutical carrier and a sufficientamount of an active ingredient selected from the amino ethanols andesters of Formula I whereby an effective dose of between 0.015 to 3millimoles per kilogram body weight is provided.

Examples 1-7, which follow, illustrate the effectiveness of2-(isopropylamino)ethanol as an antifertility agent in various animalspecies. The following are some of the features of the invention whichare illustrated by these examples. (1) When given orally at doses of 50to 100 mg./kg. to the rat, mouse, and rabbit following fertilization,fecundity is substantially reduced and in most instances pregnancy iseither reduced or prevented. Refer to Examples 5, 6 and 7. At lowerdoses litter size is reduced. Refer to Example 4. (2) In the rat asingle dose on any of the 6 days following mating is effective inreducing or preventing pregnancy. Administration on the seventh day whenimplantation of the fertilized ovum is complete is substantially withouteffect. Refer to Examples 3 and 5. (3) In the rat where litter size isreduced, offspring are, nevertheless, normal in size and appearance.Refer to Examples 4 and 5. A similar effect occurs in the rabbit in thesame dosage range. Refer to Example 7.

Attempts have been made to ascertain the mechanism by which the presentinvention operates, but no definite proposal can be offered at thistime. The diphenylethylenes and the triphenylethylenes and ethanesreferred to above and other estrogenic compounds are thought to act byaccelerating tubal transport of the ovum resulting in its arrival in theuterus prior to the time when the uterus is ready for implantation tooccur. This mechanism does not appear to be operant in the presentinstance, however. Experiments in rats treated with doses of2-(isopropylamino)ethanol up to 100 mgJkg. of body weight have revealedthat the rate of tubal transport is normal.

The drug appears to operate prior to the stage of placental development.This is suggested by the fact that in the rat pregnancy is blocked byadministration within the first six days following ovulation andfertilization, but not on the seventh day or later. In the rat,implantation of the blastocyst begins on the fifth day. Thus by day 7,placental development apparently has proceeded to the point where thedrug is no longer effective.

The foregoing provides a guide for selecting an appropriate dosageschedule for the substances of Formula I for a specific mammal. Theperiod required for irnplantation following ovulation has been estimatedfor many of the mammals of importance. Refer to Reproductive Physiologyof Vertebrates by van Tienhoven, Saunders, 1968. The following listcontains figures which are quoted form that text book. Reference is tothe time period for implantation to occur:

As an illustration of how the foregoing might be applied in a practicalsituation consider the situation of a prize dairy herd which isaccidentally invaded by a bull of an unwanted breed. In order to avoidthe expense and nusiance of dealing with a group of unwanted calves, thecows may be treated during the 20-day period following the event withthe substances of Formula I or a pharmaceutically acceptable acidaddition salt thereof. Similarly, even relatively infrequent ingestionof bait containing Formula I substances or a pharmaceutically acceptableacid addition salt thereof by mice, rats, foxes, or other pests willsubstantially reduce the fecundity thereof and thus the population overa period of time.

When pregnancy is to be prevented over a prolonged period, dosing isarranged according to a repetitive schedule which will provide fortreatment following ovulation on the assumption that fertilization hasoccured. With some animals this can easily be determined by the timewhen the animals comes into estrus. With other animals including manwhere the time of ovulation may not be known or easily determined,dosage is repeated at regular intervals which are no longer than thenormal period between ovulation and implantation and placentaldevelopment for that species. Dosage with 2-(isopropylamino) ethanol or2-(cyclopentylamino)ethanol or other Formula I substances do not alterthe estrus cyce. Another way is to simply administer a dose whenevercoitus occurs.

One of the advantages of the present invention is that no estrogenicaction is exerted by administration of 2- (isopropylamino)ethanol orother amino alcohols and esters of Formula I or suitable salts thereof.A number of the side effects attributable to current oral contraceptivesare believed to be a corollary of the estrogenic action thereof. One ofthe objects of current research in the field has been to find aneffective oral contraceptive agent which is free of estrogenicproperties. Such has been achieved by the present invention. Lack ofestrogenicity is suggested by the experiments referred to above in whichit was observed that the compound is without effect on the estrus cycleor on the rate of tubal transport. This was confirmed by testing foruterotropic activity in the immature mouse by the method of Edgren,Proceedings of the Society for Experimental Biology and Medicine, Vol.92, page 569 (1956). Thus the uterine weights of immature mice treatedwith up to 300 mg./kg. of 2-(isopropylamino)ethanol hydrochloride or2-(cyclopentylamino)ethanol hemimucate orally on each of threesuccessive days prior to sacrifice were found to be no greater than theuterine weights of untreated control mice within the limits ofstatistical significance.

Further confirmation of the lack of estrogenic properties was obtainedby evaluation of 2-(isopropylamino)- ethanol or2-(cyclopentylamino)ethanol in the vaginal cornification test in the rataccording to a standard technique (Methods in Hormone Research, IIDorfman, Academic Press, 1962, pages 65-80). A negative response wasobtained with doses of up to 250 mg./kg. of 2-(isopropylamino)ethanol asthe hydrochloride or up to 700 mg./kg. of 2-(cyclopentylamino)ethanolhemimucate. In rats the periodicity of whose estrus cycle had been established by microscopic examination of vaginal smears, it was found thatoral doses of mg./kg. of 2-(isopropylamino)ethanol hydrochloride or 700mg./kg. of Z-cyclopentylamino)ethanol hemimucate did not alter thecycle. In an additional test, a state of pseudopregnancy was induced inrats which were then treated with 100 mg./kg. of2-(isopropylamino)ethanol hydrochloride or 700 mg./ kg. of2-(cyclopentylamino)ethanol hemimucate. It was observed that theduration of the pseudopregnant state was not altered by this treatment.Substances having hormonal activity such as estrogens or progestogensalter the duration of pseudopregnancy. Fertilized rats treated with2-(isopropylamino)ethanol that nevertheless, whelped, albeit withlitters of reduced size, were observed to have normal periods ofgestation, another sign that the compound lacks an estrogenic action.

The oral elficacy of other substances characterized by Formula I in thefertility control process of the present invention is illustrated byExamples 9 to 21. These examples demonstrate that the compounds embracedby Formula I are effective fertility control agents when orallyadministered to rats at dosages ranging from about 0.1 millimole to 3millimole of active ingredient per k'lograrn body weight.

Using the preceding description, it is believed that one skilled in theart can practice the present invention to its fullest extent. Thefollowing specific embodiments are, therefore, to be construed as merelyillustrative and not limitative in any way whatsoever.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS Example 1.Effect of MultipleSubcutaneous Doses on Implantation Rate in the Rat Mature female rats ofthe Wistar strain weighing between 200 and 300 g. were mated to maleanimals of the same strain. Day 1 was designated as that day on whichsperm was first observed in a vaginal smear after caging the animalstogether. The animals of one group were untreated except for injectionof the oil vehicle. Those of another group were treated by subcutaneousinjection with a dose of 25 mg./kg. of 2-(isopropylamino)ethanol as thefree base suspended in MCT oil, and those of the third group with 50mg./kg. administered in the same manner. MCT oil is a medium chaincoconut oil fraction comprised of about 95% by weight of triglyceridesof octanoic and decanoic acids. The animals were dosed each day for thefirst six days after mating. On the eighth day the animals weresacrificed and both uterine horns were removed and examined forimplantation sites. Results obtained are listed below:

Daily Dose Percent with (mg/kg.) implantation sites None 100 Example2.-Effect of Multiple Oral Doses on Implantation Rate in the Rat Theexperiment described in Example 1 was repeated except that dosing was bythe oral route employing an aqueous solution containing the appropriateamount of 2- (isopropylamino)ethanol. The following results wereobtained:

Daily Dose Percent with (mg/kg.) implanation sites None 100 Example3.-Effect of a Single Oral Dose on Pregnancy Rate in the Rat Groups ofmated female rats were prepared as described in Example 1 and arrangedfor treatment respectively on days 6 and 7 after coitus with a singleoral dose of Z-(isopropylamino)ethanol as the hydrochloride salt. Threegroups were used for each treatment day. One group served as control andreceived water only, the second group received 50 mg./kg. of thecompound as the hydrochloride in aqueous solution, and the third group100 mg./kg. The animals were subsequently sacrificed and the uteriexamined for implantation sites. Any animal exhibiting at least oneimplantation site was considered to be pregnant. The following resultswere obtained:

Example 4.Eifect on Litter Size and Offspring on Oral Treatment of MatedFemale Rats Four groups of mated female rats containing 10 animals werearranged for oral treatment. One group served as control and was treatedonly with water, which was used as vehicle. The animals of the otherthree groups respectively received 30, 35 and 40 mg./kg. of body weightof 2-(isopropylamino)ethanol on each of the first three days aftermating. The animals were allowed to go to term and the size of thelitters and the weights of the individual pups were determined. Each pupwas examined for abnormalities. All pups were found to be normal inappearance. The numerical results are arranged in the following table:

Number Mean Mean pup whelping" litter size weight (g.)

Dose (mg/kg):

0 3 12. 6 6.0 1 "i "if i 0 Of 10 mated animals.

Example 5.Effect of Single Dose Oral Treatment of Mated Female Rats onLitter Size and Offspring administered. They served as control groups.Two oral dosage levels, 50 mg./kg. and mg./kg., were evaluated for eachtreatment day. The results are given in the following table:

Example 6.-Effect of Oral Administration on Pregnancy in the Mouse Thisexperiment was conducted with mated female mice in a fashion similar tothat used with rats described in Example 3. Oral dosage withZ-(isopropylamino)ethanol as the hydrochloride was repeated daily on thefirst 3 days after mating. Again all animals were sacrificed on theeighth day and the uteri examined. The daily doses and results arelisted below:

Mean number of implants per pregnant animal Number pregnant] numbertreated Example 7.Etfect of Oral Administration on Pregnancy in theRabbit Mean number of Number pregnant number treated pregnant animalDaihy dose (mg/kg):

in this experiment fertilized rabbits were obtained by inducingovulation With an intravenous injection of 100 i.u. of human chorionicgonadotrophin followed immediately by artificial insemination. Thefollowing day was desig- 20 nated day 1 of pregnancy.

Example 8.Capsule for Oral Administration (a) 2-(Isopropylamino)ethanolHemi-mucate.A solu- With 105 g. (0.5 mole) of mucic acid. The solutionis 25 filtered while warm and allowed to cool. The hemi-mucate tion of103 g. (1 mole) of 2-(isopropylamino)ethanol in 200 ml. of ethanol iswarmed on a steam bath and treated salt of 2- (isopropylamino)ethanolcrystallizes on cooling.

It is collected on a filter, washed with fresh solvent, and 30 dried;mp. 159-160 C. dec.

(b) Encapsulation.Hard gelatin capsules, size 000, are filled each with606 mg. of the salt prepared as described in the preceding paragraph.This quantity is equivimplants per 10 Examples 9-21.--Eifect of MultipleOral Doses on Pregnancy Rate in the Rat Mature female rats of the Wistarstrain weighing between 200 and 300 g. are mated to male animals of thesame strain. Day 1 of pregnancy is designated as that day on which spermis first observed in a vaginal smear after caging the animals together.Groups of 10 mated female animals are employed with one group serving asa control. The test compounds are administered orally employing anaqueous solution of the test agent with the control group receiving thedosage vehicle. The animals in each group are dosed each day for thefirst six days after mating. They are then sacrificed on either dayeight or day eighteen and autopsied. Both uterine horns are removed andexamined for implantation sites. In the vehicle treated control groups,the number of implantation sites ranges from about 10 to 13 implantationsites per rat. Thus, a decrease in the number of implantation sitesindicates that the compound tested is an antifertility agent.

The following Table I indicates results obtained with representativesubstances of Formula I. At day eight, the mean number of implants perrat is given. This number includes both normal and abnormal implantationsites since the difference between the two cannot be ascertained at thispoint. At days between 16 and 18, the difference between normal andabnormal implantation sites can be distinguished. The number of viablefetuses present correspond to normal implantation sites whereas nofetuses (alive or dead) are formed at the abnormal implantation sites.

HANOLAMINES AND ESTERS THEREO R -NHCHzCHz-OR Mean number of implantsExample Dose, Day No. R R mm./kg.* autopsied Total Viable 9 CzHs H 2.016-18 5.3 1. 2 CH CH2OH2 H 1. 7 16-18 5. 1 1. 3

11 CH3CH H 0.1 16-18 13.2 0 0. 5 s 0 0 CH3 12 CHQCHZOH H 0.85 8 3.7

19 OH; H 2.0 16-18 0 0 20 CHgCH (I? 0.5 8 0 0 H3 C CH3 21 Same asabove.- 0 0.5 8 0 0 C (CH2)14C H3 MmJkg. =millimo1e per kilogram bodyweight.

11 Example 22 1- Pyrrolidineethanol prepared according to A.

Lespagnol and I. Deprey, Bull. Soc. Chim. Fr., 606 (1961) (b.p. 6768 C.at 5 mm. Hg, N =1.4706 at a dose of 0.5 'millimole/kg. body weight for 1to 6 days atopsied at days 16-18 resulted in a mean of 11 total numberof implants and a mean of 0.4 viable number of implants.

Other substances characterized by Formula I which are useful in thefertility control process of the present invention as can bedemonstrated according to the hereinabove described test include:

2- allylamino ethanol,

2- 2-methyl-2-propenylamino ethanol,

2- 3 -methyl-2-butenylamino ethanol,

2- (3 -pentenylamino ethanol,

2- Z-butenylamino ethanol,

2- 3-cyclopentenylamino ethanol,

2- 2'-n-propylcyclopentylamino ethanol,

2- 2'-isopropylcyclopentylamino ethanol,

2- 2-methylcyclobutylamino ethanol,

2- 2'-ethylcyclopropylamino ethanol,

2- 2-cyclopentenylamino ethyl acetate,

2- 3-cyclopentenylamino ethyl acetate,

2- cyclobutylaruino ethyl acetate,

2- cyclopentlyamino) ethyl palmitate,

2- cyclopentenylamino ethyl palmitate,

2- isopropylamino ethyl stearate,

2- (cyclopentylamino) ethyl tetracosanate,

2- 3-cyclopentenylamino palmitate,

2- (cyclobutylamino ethyl Z-methylpropionate,

2- cyclobutylamino ethyl 2,2-dimethylbutanoate, 2-(cyclopcntylaminoethyl 3-methylbutanoate,

2- 2-cyclopentenylamino ethyl 3-ethylbutanoate, 2- 3 -cyclopentenylaminoethyl 3 ,3-dimethylbutanoate, 2- (cyclopentylamino ethyl benzoate,

2- 2-cyclopentenylamino ethyl benzoate.

The following Table II lists substances of Formula I wherein the lowestapproximate dose in millimoles per kilogram of body Weight per dayadministered for 1 to 6 days required to completely prevent pregnancy(no viable fetuses at day 18) in the rate is given.

TABLE II.LOWEST DOSE REQUIRED TO COMPLETELY PREVENT PREGNANCY IN THE RATMillimole/ Example kilograrn/ N 0. Compound day 232-(3-cyclopentenylamino)ethanol 0. 08 24- 2-(isopropylamino) ethanol 0.25. 2-(2-cyclopentenylamino)ethan l 0. 26- 2-(cycl0butylamino) ethanoL0. 30 27- -(cyclopent vlamino)ethanol. 0. 30 28 2-(t-butylamino)ethanol.0.50 29- l-pyrrolidineethanol 0. 60 30.1-[(2-hydroxyethyl)aminolpyrrolidine. 0. 60 812-(2-butylamino)ethanol 1. O 32- 2-(2,2-dimethylhydrazino)ethanol- 1. 033 2-(1-methylallylamino) ethanol -1.

CHEMICAL SYNTHESIS A number of the substances of Formula I which areuseful in the process of the present invention have been previouslydescribed in the chemical literature and are known to those skilled inthe art. However, in order that these substances should be readilyavailable to those persons desiring to practice the process of thepresent invention for reducing mammalian fecundity, representativeprocedures are given below for the preparation of substancescharacterized by Formula I. By adaptation of these procedures, theethanol amines and esters thereof which are listed herein can be readilyobtained as will be apparent to those skilled in the art.

Procedure 1.2- Cyclobutylamino ethanol A solution of Z-aminoethanol (8.7g., 0.14 mole) and cyclobutanone (9.99 g., 0.14 mole) in ml. of absoluteethanol, is reduced on a Paar hydrogenation apparatus employing 0.25 g.of platinum oxide catalyst. After the reduction is complete, thereaction mixture is filtered, the ethanol solvent evaporated and theresidue distilled providing 2-(cyclobutylamino)ethanol, b.p. 88.5 C. at9 mm. Hg.

Armlysis.-Calcd. for C H NO: C, 62.57; H, 11.38; N, 12.16. Found: C,62.89; H, 11.24; N, 12.12.

Procedure 2.2-(Cyclopropylamino)ethanol hemimucate Z-Chloroethanol (12.5g., 0.156 mole) is slowly added to cyclopropylamine (8.9 g., 0.156 mole)at 0 C. After completing the addition, the mixture heated to 60 C. for15 min. Potassium carbonate (21.5 g., 0.156 mole) is then added and themixture heated for an additional 3 hr. at 5060 C. The mixture is dilutedwith ether and filtered. Evaporation of the ether solvent anddistillation of the residue provides 2.4 g., of 2-(cyclopropylamino)ethanol, b.p. 72-73 C. at 9 mm. Hg. The amine base is stirred with 2.5g. of mucic acid in water to provde the hemimucate salt which ispurified by crystallization from ethanol-water. The analytically pure2-(cyclopropylamino)ethanol hemimucate has a melting point of 164.5 C.(dec.) (corn).

Analysis.Calcd. for C5H11NO"1/2 CgHmOgZ C, 46.59; H, 7.82; N, 6.79.Found: C, 46.29; H, 7.81; N, 6.69.

Procedure 3.2-(n-Propylamino)ethanol hemimucate An ethereal solutionml.) of ethyl oxalyl chloride (11.5 g., 0.0845 mole) is added dropwiseto n-propylamine (5 g., 0.0845 mole) and triethylamine (12.8 g., 0.127mole) in 400 ml. of ether at 5 C. After stirring for 16 hr., thereaction mixture is filtered and the ether solvent evaporated. Theresidue is taken up in ether, filtered and concentrated to provide asolid residue comprised of ethyl-n-propyloxalamide which is soluble inmethylene chloride.

Ethyl-n-propyloxalarnide (12.4 g"., 0.078 mole) in ml. oftetrahydrofuran is added dropwise to 5 g. of lithium aluminum hydride in150 ml. of tetrahydrofuran at a rate sufficient to maintain reflux.Reflux is continued for 16 hr. after the addition is complete and themixture then hydrolyzed by the sequential addition of 200- ml. of ether,7.9 ml. of 10% sodium hydroxide and finally 10 ml. of water withstirring for 3 hr. The mixture is filtered and the filtrate concentratedin vacuo to provide 8.0 g. of 2-(n-propylamino)ethanol. This material isdistilled to provide 4.4 g. of oil having a boiling point of 71-73 C. at7 mm. Hg. The hemimucic acid salt is prepared according to Procedure 2and has a melting point of 157.5- 158 C. (dec.) (corr.).

AnaIysis.Calcd. for C H NO- l/2C H O C, 46.15; H, 8.71; N, 6.72. Found:C, 46.07; H, 8.83; N, 6.70.

Procedure 4.-2-(2-Methylcyclopentylamino)ethanol A solution ofZ-methylcyclopentanone (15 g., 0.15 mole) and ethanol amine (8 g., 0.13mole) in 300 ml. of absolute ethanol is reduced according to Procedure 1employing 0.25 g. of platinum oxide catalyst. The analytically pure2-(2-methylcyclopentylamino)ethanol is obtained on distillation, yield15 g., (70%), b.p. 102-103 C. at 9 mm. Hg.

Analysis.Calcd. for C H NO: C, 67.09; H, 11.96; N, 9.78. Found: C,67.12; H, 11.88; N, 9.86.

Procedure 5.--2-(2-Propylamino)ethyl acetate hydrochloride Acetylchloride (7.85 g., 0.1 mole) is added dropwise to a stirred solution of2-(2-propylamino)ethanol (10.3 g., 0.11 mole) in 25 ml. of acetic acid.After stirring for 1 hr. the reaction mixture is concentrated in vacuoproviding a residual oil which is dissolved in chloroformhexane. Coolingthe chloroform-hexane solution yields 7.05 g. of a solid material.Crystallization of this material from butanone provides analyticallypure 2-(2-propylamino)ethyl acetate hydrochloride having a melting pointof 124-125 C. (corn).

Analysis.Calcd. for C H NO -HCl: C, 46.28; H, 8.88; N, 7.71; CI, 19.51.Found: C, 46.25; H, 8.91; N, 7.77; Cl, 19.64.

Procedure 6.-2- (2-Propylarnino ethyl palrnitate hydrochloride Palmitoylchloride (65.7 g., 0.243 mole) is added to a solution of2-(2-propylamino)ethanol (24.65 g., 0.263 mole) in 150 ml. ofchloroform. The mixture is stirred for 16 hr. and then concentrated invacuo. Crystallization of the resulting residue first from benzene thenfrom isopropyl alcohol provides 14.1 g. of analytically pure 2-(2-propylamino)ethyl palmitate hydrochloride, m.p. 107- 108 C. (corn).

Analysis.Calcd. for C H NO -HCl: C, 66.72; H, 11.73; N, 3.70; Cl, 9.38.Found: C, 66.96; H, 11.84; N, 3.71; Cl, 9.31.

Procedure 7.2- (2,2-Dimethylhydrazino ethanol Glycolaldehyde (9.89 g.)and p-toluenesulfonic acid are added to 50 ml. of dimethylhydrazine in150 ml. of absolute ethanol at C. The mixture is stirred with 4A- Lindemolecular sieve at room temperature for 28 hrs. under an atmosphere ofnitrogen, filtered and concentrated under reduced pressure. Distillationof the residual oil yields 14.3 g., of 2-(2,2-dimethylhydrazono)ethanol,b.p. 7273 C. at 9 mm. Hg.

The 2- (2,2-dimethylaminohydrazono)ethanol hydrazone intermediate isadded to sodium cyanoborohydride (8.82 g., 0.14 mole) in 500 ml. ofabsolute ethanol cooled in an ice bath followed by concentratedhydrochloride acid (11.7 ml., 0.14 mole). After stirring at roomtemperature for 16 hrs., 33% potassium carbonate is added and themixture extracted with a mixture of methylene chloride-ether. Themethylene chloride-ethereal extract is first dried over sodium sulfate,concentrated and the residue then taken up in methylene chloride andsodium sulfate added thereto. After stirring, the solution is decantedand the residual material re-extracted with methylene chloride. Thecombined methylene chloride extracts are dried over calcium sulfate,concentrated and distilled to provide 2-(2,2-dimethylhydrazino)ethanol,b.p. 61 C. at 9 mm. Hg.

Analysis.Calcd. for C H N O (percent): C, 46.13; H, 11.61; N, 26.90.Found (percent): C, 46.70; H, 11.91; N, 24.96.

NMR 6 (p.p.m.) (CDCl tetramethylsilane ref.), 2.42 [.v, 6H, N(Cg 2.82 [t(J=5.5 Hz), 2H, N 3.63 [t (J=5.5 Hz), 2H, OCfl 3.37 (broad s, 2H, 0g,NE).

Procedure 8.-1-[ (2-Hydroxyethyl) amino] pyrrolidine An etherealsolution (200 ml.) of ethyl oxalyl chloride (16.49 g., 0.12 mole) isadded dropwise to l-aminopyrrole (8.23 g., 0.96 mole) and 20 ml. oftriethylamine in 100 ml. of ether at ice bath temperature. Stirring iscontinued with cooling at 0 C. for 4 hrs. and then for a period of 14hr. at room temperature. The reaction mixture is filtered, the ethersolvent evaporated and the residue distilled to provide a fractionhaving a boiling point of 117-125 C. at 0.08 mm. Hg. The distilledmaterial is taken up in chloroform and washed with a two-fold volume of33% potassium carbonate. After drying the chloroform fraction oversodium sulfate, the solution is concentrated and distilled to yield 11.7g. of the hydrazide ethyl-N-pyrrolidinyloxalamide, b.p. 105110 C. at0.08 mm. Hg.

Reduction of the hydrazide carried out with lithium aluminum hydrideaccording to Procedure 3 provides 3.8 g.,

1 14 of the 1-[(Z-hydroxyethyl)amino1pyrrolidine, b.p. 8391 C. at 3 mm.Hg.

Analysis.Calcd. for C H N O (percent): C, 55.36; H, 10.84; N, 21.52.Found (percent): C, 54.69; H, 10.81; N,

N NHCH1 OH; DE

NMR 6 (p.p.m.) (CDCl tetramethylsilane ref.) 1.75 [m, 4H, cg, A 2.75 [m,4H, N(cg B 2.96 [t (J=5.5 HZ), 2H, OC I:I 3.77 [t (J=5.5 Hz), 2H, OCE3.53 (broad s, 2H, 05, N H

Procedure 9.--2-( l-Methylallylamino ethanolEthyl-N-(1-methylallyl)oxalamide prepared according to Procedure 3 bythe reaction of ethyl oxalyl chloride with l-methylallylamine is reducedwith aluminum hydride. The product purified 'by distillation has aboiling point of 7575 C. at 5 mm. Hg.

Analysis.Calcd. for C H NO (percent): C, 62.57; H, 11.38; N, 12.16.Found (percent): C, 62.00; H, 11.57; N, 11.89.

NMR 6 (p.p.m.) (CDCl tetramethylsilane ref.) 1.16 [d (J=6.4 Hz), 3H, CH2.63 (broad s, 2H, 0g N H), 2.69 [t (J=5.5 Hz), 2H, NCg 3.64 [l (J=5.5Hz), 2H, OCLI 3.18 [q (6.4 Hz), 1H, NCE], 5.78 [ddd (1:6.4, 10.0, 16.0Hz) 1H, C 5.07 (m, 2H, =Cg

While we have illustrated our invention with the aid of certain specificembodiments, it will be readily apparent to those skilled in the artthat our invention is not limited to those embodiments and that variousother changes and modifications can be made without departing from thespirit of the invention or the scope of the appended claims.

What is claimed is:

1. The process for reducing mammalian fecundity which comprisesadministering to a fertilized female mammal by the oral or parenteralroutes during the period following ovulation and prior to the time whenimplantation occurs an elfective implantation preventing dose of acompound selected from the group consisting of a compound having theformula R is selected from the group consisting of lower alkyl having 2to 5 carbon atoms inclusive, lower alkenyl having 3 to 5 carbon atomsinclusive, cycloalkenyl having 4 to 5 carbon atoms, cycloalkyl having 3to 5 carbon atoms inclusive, dimethylamino, pyrrolidinyl, and an alkylsubstituted cycloalkyl wherein said alkyl substituent has from 1 to 3carbon atoms inclusive and said cycloalkyl has 3 to 5 carbon atomsinclusive; R is selected from the group consisting of hydrogen, benzoyland an alkanoyl from 2 to 24 carbon atoms inclusive; or

R NH is pyrrolidinyl and a pharmaceutically acceptable acid additionsalt of said compound.

2. The process of Claim 1 wherein said effective dose contains from0.015 to 3 millimole of said compound per kilogram of body weight ofsaid mammal.

3. The process of Claim 1 wherein 2-(isopropylamino) ethanol isemployed.

4. The process of Claim 1 wherein 2- (cyclopentylamino)ethanol isemployed.

5. The process of Claim 1 wherein 2-(cyclobutylamino) ethanol isemployed.

6. The process of Claim 1 wherein 2-(2-cyclopentenylamino)ethanol isemployed.

7. The process of Claim 1 wherein 2-(3-cyclopentenylamino)ethanol isemployed.

'8. The process of Claim 1 wherein 2-(t-butylamino) ethanol is employed.

9. The process of Claim 1 wherein l-pyrrolidine-etha- 1101 is employed.

10. The process of Claim 1 wherein 1-[2-hydroxyethyl)-amino]pyrrolidineis employed.

11. The process of Claim 1 where said salt is employed in an amountsufficient to provide an effective dose containing from 0.015 to 3millimole of said compound per kilogram of body weight of said mammal.

12. The process of Claim 1 wherein said salt is employed.

13. The process of Claim 12 wherein a pharmaceutically acceptable acidaddition salt of 2-(isopropylarnino) ethanol is employed.

14. The process of Claim 12 wherein said pharmaceutically acceptableacid addition salt is 2-(isopropylamino) ethanol hemimucate.

15. The process of Claim 12 wherein a pharmaceutically acceptable acidaddition salt of 2- (cyclopentylamino) ethanol is employed.

16. The process of Claim 12 wherein said pharmaceutically acceptableacid addition salt is Z-(cyclopentylamino) ethanol hemimucate.

17. The process of Claim 12 wherein a pharmaceutically acceptable acidaddition salt of 2-(cyclobutylamino) ethanol is employed.

18. The process of Claim 12 wherein said pharma- References Cited UNITEDSTATES PATENTS 1/1965 Gottfried et al. 424 325 X OTHER REFERENCES CancerResearch, April 1959, Vol. 19, No. 3, Part 2, pp. 32-35, 40-41 and 116.

ALBERT T. MEYERS, Primary Examiner D. R. ORE, Assistant Examiner US. Cl.X.R.

1. THE PROCESS FOR REDUCING MAMMALIAN FECUNDITY WHICH COMPRISESADMINISTERING TO FERTILIZED FEMALE MAMMAL BY THE ORAL OR PARENTERALROUTED DURING THE PERIOD FOLLOWING OVULATION AND PRIOR TO THE TIME WHENIMPLANTATION OCCURS AN EFFECTIVE IMPLANTATION PREVENTING DOSE OF ACOMPOUND SELECTED FROM THE GROUP CONSISTING OF A COMPOUND HAVING THEFORMULA